Effects of illegal artisanal gold mining on water quality and vegetation cover within Muzvezve River Catchment, Zimbabwe

Abstract

Illegal artisanal gold mining activities is a growing industry and have been identified as a significant contributor to a range of environmental disturbances in many developing countries. This paper sought to investigate the effects of illegal gold mining activities on Muzvezve River water quality and vegetation cover within the catchment. The study employed two methods to collect data: water quality sampling and determination and the normalised difference vegetation index (NDVI). The NDVI was used to assess the extent and severity of the vegetation cover changes in the illegal artisanal gold mining hotspots in the last decade (2013-2023). Water samples were taken on three sampling sites/river sections (upstream, middle and downstream) of Muzvezve River for three months and analysed for nine physico-chemical parameters (pH, EC, Fe, Hg, sulphate, cyanide, total dissolved solids, total hardness and turbidity. The data collected were analyzed using R software. The findings suggest that illegal gold mining had significant negative impacts on the quality of water in Muzvezve River. Turbidity, pH and heavy metals (Hg, Fe and cyanide) concentrations were found to be significant at various p levels. Four of the nine physico-chemical parameters (pH, Fe, Hg and turbidity) were found to be above the WHO maximum allowable levels. There was a strong positive correlation among the tested water quality parameters. NDVI values of 0.27 and 0.68 for sparse vegetation and dense vegetation were recorded in the illegal artisanal gold mining hotspots in 2013 and generally vegetation cover decreased by 20% and 8% in 2017 and 2023 respectively.